this sexual act is performed by the male, and it is when he is on the side of a swimming pool or at the beach... so he inserts his feet into two girls vaginas and then proceeds to "plunge" into the water and uses the girls as flippers to propel himself through the water like a penguin.

i saw these two hot cunts laying out at the beach so i jammed my feet into their pussies and did the penguin plunge right into the ocean.